Recently developed micro-sampling and micro-analytical techniques have been used to determine the distribution of calcium, phosphorus and protein in individual enamel sections. Absolute values for calcium, phosphorus and protein were variable (30–40% calcium, 13–23% phosphorus and 0.002–0.015 mol amino acids/100 µg enamel), but consistent patterns of distribution were revealed in the tissue. The average values for calcium (37.5%), phosphorus (17.5%) and Ca:P ratio (2.1) agreed with those quoted in the literature. The volume of tissue occupied by the mineral and the significance of the composition patterns with respect to enamel formation and caries are dis